1. Field of the Invention
The present invention pertains to pouch filling machines having a plurality of filling systems, and more particularly relates to a no pouch--no fill mechanism which is responsive to a vacuum detection system and to a memory system for the filling machine.
2. Description of the Prior Art
No pouch--no fill mechanisms are well known in the art and prevent a filling system from operating in the event a pouch or bag is not present to receive the product from a single filling head, or a pouch is present but is improperly opened.
U.S. Pat. No. 2,689,073 which issued to Twigg on Sept. 14, 1954 discloses a filler for bags which are opened by suction cups. If one or both of the suction cups do not properly engage the bag, a pressure switch will not be subjected to a sub-atmospheric pressure that is great enough to close the switch thereby preventing discharge of material from the single filler. However, this patent does not disclose the combination of a vacuum detection system and a mechanical memory system which makes it possible to prevent the discharge of material at two different filling stations unless the bag is present and properly opened to receive the material at the two stations.
U.S. Pat. No. 3,427,780 which issued to Bock on Feb. 18, 1969 discloses a pouch opening system using suction cups. If the suction cups are not properly gripping a bag, insufficient vacuum will be present and a switch will remain open thus preventing a discharge of material from a single filling valve in the absence of a properly positioned and opened pouch.
U.S. Pat. No. 3,589,410 which issued to Manas on June 29, 1971 discloses a rotary turret filler having a no container--no fill device which permits the discharge of a product into a container only when a container is present under an associated filling valve and is lifted upwardly into filling position against the valve.